Which metric scale term is used to describe illumination?

The term that is used to describe illumination is "lux." Lux is a metric unit of illuminance, which measures how much luminous flux is spread over a given area. It specifically quantifies the intensity of light that hits a surface and is crucial in evaluating how well-lit an area is, especially in the context of surveillance and CCTV systems.

Using lux to assess illumination is fundamental in determining the effectiveness of CCTV cameras, as adequate lighting is essential for clear image capture. Understanding and measuring light levels in lux can help in planning the placement of cameras, ensuring that they function properly under varying light conditions.

While other options like candela relate to light intensity, they do not measure the amount of light illuminating a specific area, which is what lux specifically addresses. Parallax pertains to depth perception and angles, while joules relate to energy, not directly to illumination levels.